wallet_addEthereumChain
Creates a confirmation asking the user to add the specified chain to the wallet application. The caller must specify a chain ID and some chain metadata. The wallet application may refuse or accept the request. null is returned if the chain is added, and an error otherwise. Introduced by EIP-3085.
Params
(1)1. AddEthereumChainParameter (required)
The chain ID as a 0x-prefixed hexadecimal string, per the eth_chainId method. MetaMask compares this chain ID value with the eth_chainId return value. If these values aren't identical, MetaMask rejects the request.
(Optional) One or more URLs pointing to block explorer sites for the chain.
A human-readable name for the chain.
(Optional) One or more URLs pointing to reasonably sized images that can be used to visually identify the chain. NOTE: MetaMask will not currently display these images. Values can still be included so that they are utilized if MetaMask incorporates them into the display of custom networks in the future.
Describes the native currency of the chain using the name, symbol, and decimals fields.
A non-negative integer.
A human-readable name.
A human-readable symbol.
One or more URLs pointing to RPC endpoints that can be used to communicate with the chain. At least one item is required, and only the first item is used.
Result
(AddEthereumChainResult)Errors
| Code | Message |
|---|---|
| -32602 | Expected null or array with at least one valid string HTTPS URL 'blockExplorerUrl'. Received: ${blockExplorerUrls} |
| -32602 | Expected 0x-prefixed, unpadded, non-zero hexadecimal string 'chainId'. Received: ${chainId} |
| -32602 | Invalid chain ID "${_chainId}": numerical value greater than max safe value. Received: ${chainId} |
| -32602 | May not specify default MetaMask chain. |
| -32602 | Expected 2-6 character string 'nativeCurrency.symbol'. Received: ${ticker} |
| -32602 | nativeCurrency.symbol does not match currency symbol for a network the user already has added with the same chainId. Received: ${ticker} |
Example
Request
await window.ethereum.request({
"method": "wallet_addEthereumChain",
"params": [
{
"chainId": "0x64",
"chainName": "Gnosis",
"rpcUrls": [
"https://rpc.gnosischain.com"
],
"iconUrls": [
"https://xdaichain.com/fake/example/url/xdai.svg",
"https://xdaichain.com/fake/example/url/xdai.png"
],
"nativeCurrency": {
"name": "XDAI",
"symbol": "XDAI",
"decimals": 18
},
"blockExplorerUrls": [
"https://blockscout.com/poa/xdai/"
]
}
]
});
Result
"null"